1. Field of the Invention
The present invention relates to a technology used to retain the quality of data communication services including video streaming or the like.
2. Description of the Related Art
In the past, retransmission control, rate control, forward error correction (FEC) denoting an error correction technology, error concealment (EC) denoting an error concealment technology, and so forth have been widely known, as technologies achieved for QoS (the quality of communication services) control performed through end-use apparatuses including a transmission apparatus and a reception device that are used for the video streaming.
Each of the above-described technologies has been contemplated in various quarters. There are known technologies for adding sophisticated control performed considering the congestion state of the network band.
Thus, when a video streaming system is considered, the following rate control technology is used. Namely, even though video is transmitted while avoiding errors occurring on the video-data distribution side at the video-data transmission time, a technology for recovering from errors by retransmitting a lost packet, for example, is used. Further, a method of performing multiple controls has been contemplated, so as to add a technology of concealing errors fixed on the video-streaming-reception side with difficulty. Still further, when various types of error resistance technologies can be controlled at the video-streaming-transmission time and expected operations are executed, it is predicted that the QoS control can be performed for high-quality video streaming transmission with a high probability.
Japanese Patent Laid-Open No. 2007-28623 discloses the technology for adding a retry flag to a packet, the retry flag indicating that a system on the reception side should not try to perform the packet retransmission when an error is predicted in the packet.
However, even though the QoS control is thoroughly performed at each of points including the video-streaming transmission side, the video-streaming reception side, or a band therebetween, the most appropriate result is not necessarily obtained. This is because when error resistance processing is performed at each point, the QoS resource is used at each point, which increases the load on the QoS resource in the system as a whole. Therefore, even though no trouble occurs when a single streaming video data item is distributed, troubles may occur when a person distributes a plurality of streaming video data items. Further, when a plurality of streaming video data items is transmitted by a plurality of users via a network line and a plurality of applications is used in a personal computer (PC) terminal of a person, troubles may occur in different streaming video and/or applications. Particularly, since the retransmission of streaming video is performed for packet losses occurring when packets are transmitted through a narrow band and when the band is congested, the state of the band may be deteriorated due to the streaming-video retransmission.
Further, according to the technology disclosed in Japanese Patent Laid-Open No. 2007-28623, no consideration is given to the multiple-control method including the error correction technology and the error concealment technology.